Unstable Sattelite Dish

I called dstv installer(dish relocation) by the name Wendy ***,for the dstv account ***6 on the 25th of June 2019,and she sent her agents to come and do the installation,the guys came very late around 7pm and they forced to do the job although it was dark, the dish has 4 bolts to be drilled on the wall and instead they drilled only 2,the dish is unstable and the channels jam whenever there's windy because the dish is shaking and unstable, I laid the complaint with her on the 1st of July and she promised to send the guys to fix their mess but they never showed up, I have sent her close to 4 emails asking her to send the guys she keeps saying she will send someone to fix it but that never happened, the worse scenario to happen is that as unstable as the dish is it might fall on top of my cars and damage the house windows as well. I paid the installer in full an amount of R400 and Wendy even sent me an email with the payment invoice but the job is not satisfactory.